Contaminants
in Farm Raised Salmon Suggest Restrictions in Consumption(Beyond
Pesticides, January 12, 2004) A study published in the
January 9th issue of Science (vol. 303, 2004) found significantly
higher levels of cancer-causing and other health-related contaminants
in farm raised salmon than in their wild counterparts. Concentrations
of several cancer-causing substances in particular are high enough to
suggest that consumers should consider severely restricting their consumption
of farmed salmon, according to the study's authors. Analyzing fillets
from about 700 farmed and wild salmon produced in eight major farmed
salmon producing regions around the world and purchased in 16 large
cities in North America and Europe, the study, "Global
Assessment of Organic Contamination in Farmed Salmon," is the
largest and most comprehensive study done to date. Four substances that
have been well studied for their ability to cause cancer - PCBs, dioxins,
dieldrin and toxaphene were consistently and significantly more concentrated
in farmed salmon as a group.

In most cases, as
detailed in the study, consumption of more than one meal of farmed salmon
per month could pose unacceptable cancer risks according to U.S. Environmental
Protection Agency (EPA) methods for calculating fish consumption advisories.
The majority of salmon served in restaurants and found on grocery store
shelves is farmed rather than wild.

Among the study's
conclusions, salmon farmed in Europe were generally more contaminated
than farmed salmon from North or South America. Farmed salmon purchased
for the study from supermarkets in Frankfurt, Edinburgh, Paris, London,
and Oslo were the most contaminated and triggered consumption recommendations
of four to eight ounces per month - based on U.S. EPA consumption advisories
for these contaminants.

Farmed salmon purchased
from supermarkets in Los Angeles, Washington, D.C., Seattle, Chicago,
New York, and Vancouver triggered a recommendation of no more than 16
ounces per month. There was slightly more variation in fish purchased
in North America than those purchased in Europe. While farmed salmon
purchased for the study in New Orleans and Denver were generally least
contaminated - triggering a recommendation of about 24 ounces, or three
meals, per month - farmed salmon purchased in Boston, San Francisco,
and Toronto triggered the more stringent consumption recommendations
of the European-purchased fish.

"Ultimately,
the most important determinant of risk has to do with where the fish
is farmed not where it is purchased," said Dr. David Carpenter,
an author of the study and Director of the Institute for Health and
the Environment at the University at Albany. "And because it's
a global market, it's hard to be sure what you're getting." According
to Carpenter, "Just because Europeans have the most contaminated
farmed salmon, this doesn't mean American consumers shouldn't be concerned."

With very few exceptions,
farmed salmon samples tested significantly exceeded the contaminant
levels of wild salmon, which could be consumed at levels as high as
8 meals, or 64 ounces, per month. Even the least contaminated farmed
salmon, from Chile and the state of Washington, had significantly higher
levels of PCBs, dioxins, and dieldrin than wild salmon.

The Pew-sponsored
study concluded that the contamination problem is likely related to
what salmon are being fed when they're on the farm. While wild salmon
eat a diverse buffet from small aquatic organisms like krill to larger
fish, farmed salmon are fed a concentrated and high fat mixture of ground
up fish and fish oil. And since chemical contaminants a fish is exposed
to during its life are stored in its fat, the higher fat "salmon
chow" passes along more of these contaminants to the farmed salmon.

Given the overall
contaminant levels found, if these were locally caught fish instead
of fish purchased commercially EPA and many state consumption advisories
would suggest that consumers restrict their consumption of farmed salmon
to an average of no more than one eight once meal per month. However,
consumers need to be aware that in some cases even that could exceed
advised contaminant exposure levels. EPA's consumption advisories use
acceptable lifetime risk levels to identify the maximum number of fish
meals per month that can be safely eaten.

"If anything,
the study conservatively estimates the health risks from the contaminants
in farmed salmon," said the University at Albany's Carpenter. The
EPA fish consumption guidelines don't take into account exposures people
have to the same cancer-causing substances from all other sources in
the environment. "They assume," said Carpenter, "that
fish consumption is the only source of exposure people have to these
substances; and we know that's not true." "Also," according
to Carpenter, "the recommendations only consider the risk of cancer
and don't take into account the neurological, immune, and endocrine
system effects that have been associated with these contaminants."

Consumers interested
in knowing whether salmon is wild or farmed should be aware that the
word "Fresh" on the label does not mean the salmon is wild-caught
from the ocean. And any salmon labeled "Atlantic" in the U.S.
and in other countries is most likely farmed. The authors recommended
that governments require clear and prominent labeling of farmed and
wild salmon as well as the country of origin of all farmed salmon.

The authors also
said their results strongly reinforced the recommendations of a July
2003 National Academy of Sciences report on dioxins in the food supply
which called for reducing dioxin levels in animal feed such as fishmeal.
Since contaminants build up in the fatty tissue of the fish, the authors
point out that consumers may be able to reduce their consumption of
contaminants in farmed salmon by following the recommendations of many
state governments and the federal government to remove as much skin
and visible fat as possible. However, it is difficult to determine how
much of the contaminant load can be removed in this way.

In assessing the
human health risks of consuming farmed salmon, the authors of the study
used U.S. EPA consumption guidance for PCBs, toxaphene, and dieldrin
covering locally caught fish rather than U.S. Food and Drug Administration
(FDA) standards for these substances governing commercially-sold fish
because EPA's recommendations are based on health effects only. While
FDA is the agency that actually regulates contaminants in commercial
fish, unlike EPA FDA does not have consumption standards for toxaphene
in fish, and the agency's standards for PCBs and dieldrin weren't set
using purely health-based criteria. According to Dr. Barbara Knuth of
Cornell University and one of the study's authors, "Because the
FDA regulatory levels take into account factors such as effects on the
food production system, they were never designed to consider exclusively
human health risk-which was the only concern we were looking at in this
study."

"Plus,"
said Knuth, "the health and diet information and the technology
FDA used to help set the regulatory levels for PCBs are 20 years out
of date. We can detect PCBs at much lower levels today; new studies
provide more information about the health risks associated with these
substances; and people eat more fish today." Knuth said, "It's
this vast difference in the approach of the two agencies that explains
why farmed salmon with these levels of contaminants could trigger such
restrictive consumption recommendations based on EPA methods, but is
still allowed to be sold legally in the U.S. by the FDA."

The annual global
production of farmed salmon has increased 40 times during the last two
decades - making inexpensive salmon available to consumers year-round.
Between 1987 and 1999, salmon consumption increased at an annual rate
of 14% in the European Union and 23% in the U.S. Since 2000, over half
of the salmon eaten globally has been farmed, coming primarily from
fish farms in Northern Europe, Chile, and Canada.